Fast-forward several years: the price of Bitcoin has skyrocketed, and so has the value of their investment. And they have also racked up "an additional $350 million or so" of other virtual currencies, most of it in Ethereum.

The twins said they might think about selling when the value of all Bitcoin in circulation is on par with all the gold in the world — about $7-8 trillion compared to the $310 billion value of all Bitcoin on Tuesday. But Tyler Winklevoss added that even that might not be the tipping point since "Bitcoin is more than gold."

Bitcoin's price has exploded over the last two years. Its rapid ascent, and the cottage industry that has started to grow around it, have both galvanized investors' interests and elicited their fair share of criticism.

Earlier this year, JPMorgan CEO Jamie Dimon called it "a fraud" that is "worse than the tulip bulbs," referring to the 17th century Dutch tulip-mania bubble.

People outside the finance world have started to take notice as the price of Bitcoin keeps soaring higher. Some have even started to do creative things to get in on the action, like taking out mortgages to buy Bitcoin or purchasing the cryptocurrency with credit cards.

But, as the NYT put it, the Winklevoss' experience might be a good, cautionary reminder for regular investors that "the biggest winners have been a relatively small number of early holders who had plenty of money to start with and have been riding a price roller coaster for years."